It works pretty well.
You search for something local, be it movie theaters, places to eat, barber shops and so on and if someone has something to say about it on Foursquare, Bing may show it.
For example, I searched for Dunkin Donuts and this is what came up:
I am highlighting one of three Foursquare reviews that show up. Note, there are also comments from Twitter and Facebook users for this query in the Bing social bar.
The only issue? This can become a headache for local stores worrying about customers trashing them and it showing up in Bing for searches on their name.
A WebmasterWorld thread has one member saying:
Great now I see this is really going to kick in the ransom demands to a business. "Pay me this or our network will write all these bad reviews". In the news the other day how companies are getting these pay up to shut us up demands. I am soooo leary of this anyway but the general public makes decisions from these reviews, just wonder how will this play out.
Here is a video:
Forum discussion at WebmasterWorld.